Conversion of direct process high-boiling component to silane monomers in the presence of hydrogen gas

Abstract

The present invention is a process for converting a high-boiling component resulting from the reaction of an organochloride with silicon into commercially more desirable monosilanes. The process comprises contacting the high-boiling component with hydrogen gas at a temperature within a range having a lower limit greater than 250° C. and an upper limit of 1000° C. Yield of the present process may be improved by use of a catalyst selected from a group consisting of activated carbon, platinum metal, platinum supported on alumina, palladium supported on carbon, SbCl 5 , H 2 PtCl 6 , BCl 3 , AlCl 3 , and AlCl 3 supported on a support material selected from a group consisting of carbon, alumina, and silica. In a preferred embodiment of the present process the process is run at a pressure within a range of about 250-1000 psig. The present process is preferential for the production of diorganodichlorosilane in relation to organotrichlorosilane in the monosilane product.

We claim: 
     
       1. A process for converting a high-boiling component resulting from the reaction of an organochloride with silicon, to monosilanes, the process comprising: contacting a high-boiling component, resulting from the reaction of an organochloride with silicon, and hydrogen gas at a temperature within a range having a lower limit greater than 250° C. and an upper limit of 1000° C. 
     
     
       2. A process according to claim 1, where the temperature is within a range of about 270° C. to 650° C. 
     
     
       3. A process according to claim 1, where the high-boiling component and hydrogen are contacted at a pressure within a range of about zero psig to 3,000 psig. 
     
     
       4. A process according to claim 1, where the high-boiling component and hydrogen are contacted at a pressure within a range of about 250 psig to 1,000 psig. 
     
     
       5. A process according to claim 1, where the ratio of the weight of the high-boiling component to the weight of the hydrogen gas is within a range of about 0.1:1 to 1OOO:1. 
     
     
       6. A process according to claim 1, where the ratio of the weight of the high-boiling component to the weight of the hydrogen gas is within a range of about 1:1 to 500:1. 
     
     
       7. A process according to claim 1, where the high-boiling component results from the reaction of methyl chloride with silicon. 
     
     
       8. A process according to claim 1, where the high-boiling component comprises polysilanes and silalkylenes. 
     
     
       9. A process according to claim 1, where the high-boiling component comprises polysilanes described by formula R a  H b  Si n  Cl 2n+2-a-b , where each R is a radical independently selected from a group consisting of alkyls comprising one to six carbon atoms, n=2 to 20 , a=0 to 2n+2, b=0 to 2n+2, and a+b=0 to 2n+2. 
     
     
       10. A process according to claim 1, where the high-boiling component comprises silalkylenes comprising one or more silalkylene bonds described by formula Si(C) z  Si and z=1, 2, or 3. 
     
     
       11. A process according to claim 1, where the high-boiling component comprises soluble and insoluble compounds of copper, aluminum, and zinc. 
     
     
       12. A process according to claim 1, where the monosilanes comprise diorganodichlorosilane and organotrichlorosilane and the ratio of the diorganodichlorosilane to the organotrichlorosilane is greater than about 1.0. 
     
     
       13. A process for converting a high-boiling component resulting from the reaction of an organochloride with silicon, to monosilanes, the process comprising: contacting a high-boiling component, resulting from the reaction of an organochloride with silicon, and hydrogen gas at a temperature within a range having a lower limit greater than 250° C. and an upper limit of 1000° C., in the presence of a catalyst selected from a group consisting of activated carbon, platinum metal, platinum support on alumina, palladium supported on carbon, AlCl 3 , SbCl 5 , H 2  PtCl 6 , BCl 3 , AlCl 3 , and AlCl 3  supported on a support material selected from a group consisting of carbon, alumina, and silica. 
     
     
       14. A process according to claim 13, where the catalyst is selected from a group consisting of platinum metal, platinum supported on alumina, palladium supported on carbon, AlCl 3 , SbCl 5 , H 2  PtCl 6 , BCl 3 , AlCl 3 , and AlCl 3  supported on a support material selected from a group consisting of carbon, alumina, and silica. 
     
     
       15. A process according to claim 13, where the catalyst is selected from a group consisting of activated carbon and platinum metal supported on alumina. 
     
     
       16. A process according to claim 13, where the catalyst is activated carbon. 
     
     
       17. A process according to claim 13, where the temperature is within a range of about 270° C. to 650° C. 
     
     
       18. A process according to claim 13, where the high-boiling component and hydrogen are contacted at a pressure within a range of about zero psig to 3,000 psig. 
     
     
       19. A process according to claim 13, where the high-boiling component and hydrogen are contacted at a pressure within a range of about 250 psig to 1,000 psig. 
     
     
       20. A process according to claim 13, where the ratio of the weight of the high-boiling component to the weight of the hydrogen gas is within a range of about 0.1:1 to 1000:1. 
     
     
       21. A process according to claim 13, where the ratio of the weight of the high-boiling component to the weight of the hydrogen gas is within a range of about 1:1 to 500:1. 
     
     
       22. A process according to claim 13, where the high-boiling component results from the reaction of methyl chloride with silicon. 
     
     
       23. A process according to claim 13, where the high-boiling component comprises polysilanes and silalkylenes. 
     
     
       24. A process according to claim 13, where the high-boiling component comprises polysilanes described by formula R a  H b  Si n  Cl 2n+2-a-b , where each R is a radical independently selected from a group consisting of alkyls comprising one to six carbon atoms. n=2 to 20, a=0 to 2n+2, b=0 to 2n+2, and a+b=0 to 2n+2. 
     
     
       25. A process according to claim 13, where the high-boiling component comprises silalkylenes comprising one or more silalkylene bonds described by formula Si(C) z  Si and z=1, 2, or 3. 
     
     
       26. A process according to claim 13, where the high-boiling component comprises soluble and insoluble compounds of copper, aluminum, and zinc. 
     
     
       27. A process according to claim 13, where the monosilanes comprise diorganodichlorosilane and organotrichlorosilane and the ratio of the diorganodichlorosilane to the organotrichlorosilane is greater than about 1.0. 
     
     
       28. A process according to claim 9, where R is methyl. 
     
     
       29. A process according to claim 24, where R is methyl. 
     
     
       30. A process according to claim 1, where the organochloride is methyl chloride and the high-boiling component comprises polysilanes, silalkylenes, silicon containing solids, and soluble and insoluble compounds of copper, aluminum, and zinc. 
     
     
       31. A process according to claim 13, where the organochloride is methyl chloride and the high-boiling component comprises polysilanes, silalkylenes, silicon containing solids, and soluble and insoluble compounds of copper, aluminum, and zinc.